Titan (MCU)
Titan was plagued by overpopulation, which caused a drain on its resources and sent the Titan race hurtling towards a societal cataclysm. Thanos, son of a royal family, proposed randomly killing half the planet's population as a way to preserve their finite resources, but his plan was rejected as too extreme, and he was cast out as a madman. The predicted catastrophe then hit Titan, causing the mass extinction of most of the planet's lifeforms, with Thanos being one of the few remaining survivors.